When an image which has been recorded in a digital format is recorded onto a recording medium such as a paper sheet and film, or conversely when an image which has been recorded on a recording medium is picked up by an image pickup apparatus such as scanner or the like, the quality of those images are greatly affected by recording properties of the recording device, the medium properties of the recording medium, or the image pickup properties of the image pickup apparatus.
In particular, with the recording devices and the image pickup apparatuses employing plural recording units (e.g., heads) or plural image pickup units (e.g., CCDS) having a smaller area than the area of the recording area on the recording medium, recording of an image on a recording medium or image picking up is performed while relatively moving these units with respect to the recording medium, thus leading to a problem of the image quality by being greatly affected by geometric properties such as the positional relation between the plural recording units or between the plural image pickup units; the mechanical error during movement of these units; and so forth.
For example, with a color ink jet printer serving as a recording device including plural heads corresponding to various color inks, even slight deviation of the head position leads to failure in superimposition of dots in various colors in printing, leading to color shift, resulting in markedly deterioration in printing quality.
Accordingly, a technique as disclosed in Japanese Unexamined Patent Application Publication No. 10-278311 is known wherein a test pattern (chart) which allows the operator to easily detect color shift is printed, following which the operator checks the printed test pattern through visual monitoring and selects a pattern which exhibits the minimum color shift so as to estimate printing properties corresponding to the geometric properties of the printing device, thereby enabling image processing for correcting color shift described above.
Also, a technique as disclosed in Japanese Unexamined Patent Application Publication No. 7-40531 is known wherein two recording heads having low resolution are arrayed and fixed one to another such that the nozzles thereof are positioned so as to complement one another, thereby achieving approximately two times resolution. With such an ink jet head assembly, the heads must be mounted while precisely measuring the positional relation therebetween. In conventional techniques, the positional relation between the heads is directly measured by mechanical measurement, or the dots or lines printed by these nozzles are measured through a microscope so as to obtain the positional relation between the heads.
However, such a method wherein the operator checks the test chart for detecting deviation requires skill of the operator to a certain degree, and adjustment even by a skilled operator has the disadvantage of depending upon the intuition of the operator.
Furthermore, mechanical measurement of the head positions described above requires a precise mechanism, leading to high costs of installation of the measurement device, and high costs of maintenance after installation thereof, as well as high manufacturing costs due to the measurement, and leading to a problem of extra space for installation of the measurement device.
Furthermore, even if the most precise positioning of the heads is performed, the positional relation between the nozzles does not exactly coincide with the positional relation between the dot impact positions in printing at all times.
Furthermore, measurement of the dots or the lines through a microscope has the disadvantage of a narrow field of view of the endoscope, time consuming measurement, and a great deal of processing amount corresponding to the data amount taken by the measurement. In order to solve these problems, a relatively small number of the dots and lines should be measured. However, this leads to a new problem of deterioration in high-precision measurement due to substandard dot fixing, blot, irregularities in the dot impact position, or the like.
The present invention has been made in order to solve the aforementioned problems, and accordingly, it is an object thereof to provide a test chart, a geometric property analysis system, a geometric property analysis method, a printer, an ink-jet printer, which allow the operator to perform high-precision analysis of geometric properties of at least one of a recording device, a recording medium, and an image pickup apparatus, with a simple and precise procedure.